DemonSpawn Software
An online organization devoted to providing gamers with resources and programs. MapMaker, FUDGE and Tunnels and Trolls die rollers, all in Beta test (trial download), for PCs.
http://www.demonspawn.net

Eposic
Free online JavaScript and Java online roleplaying tools including animated Tunnels and Trolls dice roller, random event, weather, GM decision, NPC rune generators, private dice rooms for online RPGs, gallery of downloadable images.
http://www.eposic.com/

Role Playing DB.
A commercial roleplaying database manager for Linux and Windows.
http://www.deepsoft.com/cgi-bin/deepwoods.cgi/RolePlayingDB

GDSWare
Features WhosNext, an utility which is intended to help running combats with rolling for inititive and keeping track of damage for multiple characters.
http://www.geocities.com/gdsware/

DA: The Role Player's Digital Assistant
A tool designed to help create, organize, and run tabletop roleplaying games. [Shareware|Windows NT/2000/XP]
http://www.mjhkstudios.com/DA/Frameset.htm

The Adventurer's Diary
A shareware Windows database application for keeping track of events and persons the player meets.
http://adventurer.worldofbelushi.de/

The RPG-SoundMixer
A commercial program (Demo available) for Windows specifically designed for creating musical and acoustic backgrounds for roleplaying sessions. [English/German]
http://www.rpgsoundmixer.com/

AnderWare Development
Features MasterPlan, a freeware scenario-planning utility for Windows.
http://www.anderware.org/dev/

Random RPG Idea Generator
Provides game masters and players with random weapon, encounter, story, and trap ideas.
http://www.randomrpg.com

Garthac Games
Creates products that support and enhance role playing games. MageHand is a tool for creating, modifying, organizing, sharing and printing campaign information.
http://www.garthac.com

Hamete.org's Virtual Dice Server
Generates online and by-e-mail dice rolls.
http://hamete.org/dserver/dices

kLoOge.Werks - The Digital Gaming Table
A commercial Java tool which allows playing round based and map using game to be played with a computer.
http://www.kloogeinc.com/

Fantasy Grounds
An application acting as a virtual online gaming table primarily intended for pen and paper style narrative role playing games. [Windows XP/2000]
http://www.fantasygrounds.com

TenFootWiki
A self-contained wiki as a personal campaign notebook for roleplaying gamemasters.
http://www.unclebear.com/tenfootwiki/

Battlegrounds Games
A virtual tabletop software that allows to play any RPG online or offline. It is cross-platform, and includes features like Fog of War.
http://www.battlegroundsgames.com/

Dungeon Helper
Mapping and dice software to make it easier to play Pen and Paper over the Internet. [Windows]
http://dh.abomb.info

Dices
Open source online role playing software offering game profiles management for several games, die launch module, a map editor with support for placing players and NPCs on a map, automated recording of logs and notes management.
http://dices.sourceforge.net/

Codex of Universes
Online editing of worlds and campaign settings. Users can create new universes to catalog and showcase their particular setting.
http://www.codexofuniverses.com/

Obsidian Portal
Online campaign hosting and collaborative content database. Users can host a campaign weblog that ties in with tools for tracking NPCs, items, and other game content.
http://www.obsidianportal.com

Marnok's Adventure Generator
Generates random adventure ideas. Each includes an overall theme, adventure hooks, goals, major and minor villains, and optional twists.
http://marnok.com/?content=content/Role%20Playing/Adventure%20Generator.htm

Dire Press RPG Tools
Random generators for use with d20 fantasy and other role-playing game systems.
http://direpress.bin.sh/tools/